Method of welding heavy-gage tubing



H. H. BELMONT. METHOD OF WELDING HEAVY GAGE TUBING.

APPLICATION FILED JAN-17,1919.

Patentd Oct. 5, 1920.

W/lIIJW/IIl/IIlI/I/lll/f/IIl/JM/IIIIl/IWI/Ill/ LHIOHICU as it is beingwelded UNITED, STATES PATENT OFFICE.

To THE STANDARD PARTS COMPANY, OF CLEVELAND, OHIO, A CORPORATION OFOHIO.

METHOD OF WELDING HEAVY-GAGE TUBING.

Application filed January 17, 1919. Serial No. 271,618.

This invention relates to methods of weld ing the longitudinal seam intubing more particularly to tubing made of thick or heavy gage stock.

In attempts which have been made heretofore to weld the longitudinalseam in heavy gage tubing, either by the electric resistance method orby a gas flame, it has been found that the metal adjacentthe exteriorsurface of the tube will be fused and welded but the metal adjacent theinner surface of the tube will not be welded, because the heat does nothave the necessary opportunity to penetrate to the inner wall of thetube. It has, therefore, been found impracticable, heretofore, to weldtubing made of heavy gage stock, either by the electric resistancemethod or by a gas flame, and for this reason electric or gas weldedtubing has been manufactured only from the lighter gages of stock.

It is the object of this invention to provide a method of welding whichwill overcome the defects and form a perfect weld through the fullthickness of the seam, and the basic principles of the method applicableto either the electric resistance or gas flame methods of welding, but Iwill describe the invention, in this specification, as employed in themanufacture of electric welded tubing.

I have illustrated the various steps in my improved method drawings, ofwhich: Figure 1 represents a cross section of ,a strip ofmetal used inmaking a tube;

Fig. 2 is a fragmentary section through a set of rolls for scarfingthe'edges of the strip;

Fig. 3 is a transverse section of the tube, after forming and beforebeing welded;

ig. 4 is a transverse section of the tube and shown in its relaand .Specification of Letters Patent.

HARRY H. BELMONT,

heretofore experienced v the Parpart Patent which I havedevised are inthe accompanying Patented Oct. 5, 1920.

in machine;

ig. 5 is a transverse section of the tube after it has been welded; Fig.6 is a pleted tube;

Fig. 7 is a view similar showing a modification; and

Fig. 8 is a fragment ofanother view similar to Fig. 3, but showing afurther modification.

Referring to the drawings, 10 indicates tion'to the essential elementsof the-Weldto Fig. 3, but

usual squared edges, and 11 indicates the eled by the surfaces 17 and18.

After the edges have been scarfed, as

shown in Fig.

2, the strip is formed into a tube by any of the well-known formingmachines commonly in use in tube mills, the

cross section of such formed tubing being shown in Fig. 3.

Referring to Fig. the electrodes of an electric welding machine such,for example, as is illustrated in N 0. 658,741, issued September 2?,1900. he compression rolls for compressing the tubing as it is beingWeld-- ed are shown at 21 and 22. It will be observed that th line ofcontact the tube, rent flows from the electrode 19 to the electrode 20,the resistance of the line of conere is a comparatively thin between themeeting edges of transverse section of the comat, 19 and 20 represent asindicated at 23, and as the curtact 23 willcause these thin edges to berapidly. heated and as they reach the welding temperature, the pressureof the rolls 21 and 22 will force the edges together and increase thethickness of the contact until the full thickness of the tube isreached.

his operation will result in first forming a flash, or bur, 2-4 on theinterior of the tube and as the edges are forced together, a flash 25will be formed on the exterior and the seam will be welded clearthrough. After there will be contact throughout the full depth of themetal, ,the points first in con-. offering higher resistance tact, beinghotter, and forcing the current through the cooler portions and thusrapidly heating them so that, in practice, it has been found that themetal throughout the full depth of the seam reaches the melting point atpractically the same instant and a perfect weld is thus formed. 1

When it is attempted to weld a tube having a thick wall, by the methodused in the case of thin wall tubing, the current passing from oneelectrode to the other'tends to follow the outer surface of the tube anddoes not penetrate sufficiently to effect a weldinIg throu h the fullthickness of the seam. there? strip, so that the line of contact will beini-.

tially' adjacent the inner wall of the tube,

thereby forcing the current ,to first pass through and weld the innerpart of the seam.

When it is desired to avoid the production of a flash, or bur, on theinterior of the tube, the edges are scarfed, as shown in Fig. 7. Anotherpossible alternative of scarfing is shown in Fig. 8, and in thisarrangement, the initial line of contact is at themiddle of the seam.

Having thus described my invention, what I claim is:

1. The herein ing the longitudinal seam of tubing having relativelythick walls, which consists in first applying the welding medium torelatively thin contacting. edges and, as such edges reach the weldingtemperature, forcing them together tangentially to thereby increase thethickness of contact at the edges 50 to the full thickness of the walls.

, forming similarly beveled edges, ore, prefer toscarf the edges of thedescribed method of weld 2. Theherein described method of weld-- ing thelongitudinal seam of tubing having relatively thick walls, whichconsists in first applying the welding medium to the exterior of thetube to relatively-thin contacting edges adjacent the interior of thetube, and, as such contacting edges reach the welding. temperature,forcing them together to form a flash on the interior-and to increasethethickness of the contact at the edges to the full thickness of thewalls and thenlform a flash on the exterior.

e. The herein described method of welding the longitudinal seam oftubing having relatively thick walls, which consists in first passing aheating current through relatively I thin contacting edges offering arelatively high resistance, and when such edges reach a weldingtemperature, forcing them together tangentially to increase thethickness of the contact at the edges to the full thick ness and to formthe flash.

4. Theherein described method of welding the longitudinal seam of tubinghaving relatively thick walls, which consists in first forming the tube'to engage the edges in a thin line of contact within thecircumferential contour of the tube, passing a heating current throughsuch contacting edges and as the.

edges reach a welding temperature, forcing them together to increase thethickness of the contact to the full thickness of the tube and formflashes on the interior and exterior.

5. The herein described method of weld- ,ing the longitudinal seam oftubing having relatively thick walls, which consists in first bevelingthe edges so that there willbe initially a thin line ofcontact adjacentthe interior surface of the tube, passing a heating current through suchcontacting edges,

reach a welding temperaand, as the edges ture, forcin them together toincrease the thickness 0 the contact to the full thickness of the tubeand first form a flash on the interior and then on the exterior.

In testimony whereof I aflix my signature.

I HARRY H. BELMONT.

